1. Field of the Invention
The invention relates to a lamp and more particularly to a light-emitting diode (LED) lamp that can be directly mounted to a fixture prepared for a fluorescent lamp.
2. Description of Related Art
LEDs are renowned for their long life and their ability to resist shock. Also, an LED consumes much less electrical power than fluorescent lamps. Therefore, LED lighting devices are gaining popularity worldwide. Recently, LEDs as a light source have been employed in outdoor lighting devices.
However, ballasts have various types, such as instant start ballasts, rapid start ballasts, programmed-start ballasts, hybrid ballasts, and so on. For a programmed-start ballast, it can output a high-frequency voltage for preheating the filaments of a fluorescent lamp and then can output a high voltage to initiate an arc; once starting the lamp, the ballast can output an operating voltage, which is less than the preheating voltage and the initiating voltage. Thus, for replacing an existing fluorescent lamp with an LED lamp, the features of the existing ballast associated with the fluorescent lamp should be investigated. Through constant investigation on the technology of fluorescent lamps, applicant has contrived an LED lamp that can replace an existing fluorescent lamp and cooperate well with the ballast used with the existing fluorescent lamp.